WASHINGTON – A year-end deadline looming, Senate negotiators remained short of an agreement Sunday to prevent across-the-board tax increases for millions. President Barack Obama blamed Republicans for putting the nation's shaky economy at risk.

Despite indications of progress in the negotiations, Democrats said Republicans were seeking to slow future cost of living increases for Social Security recipients as part of a compromise to avoid the so-called fiscal cliff. Republicans declined to confirm the assertion – and one GOP official disputed it – but noted that Obama said in a television interview broadcast earlier in the day he had advanced such a proposal in earlier talks with Republicans.

The fate of the negotiations remained in doubt, with both the House and Senate meeting during the day, two days before the beginning of a new year that would trigger across-the-board tax increases and spending cuts that leaders in both parties have said they want to avoid.